Insulating wall unit

ABSTRACT

A wall unit comprising panels lying at opposite faces of said unit, a seal arranged between the margins of said panels, and an insulation occupying the cavity between said panels, wherein the improvement comprises at least one insulating group extending parallel to said panels and comprising two foils capable of reflecting thermal radiation and chambers lying between said foils, the walls of which consist of insulating material. The cavity between said panels may be evacuated or it may be filled with dry air or a dry gas.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part of application Ser.No. 826,958, filed May 22, 1969 and entitled "Wall Units withInsulation," now U.S. Pat. No. 3,646,721 and of application Ser. No.37,068, filed May 13, 1970 and entitled "Thermally Insulating WallUnits."

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wall unit with thermal and acousticinsulation.

2. Description of the Prior Art

A known wall unit with thermal and acoustic insulation comprises twosheet metal panels of equal size, sealing strips of resilient materialarranged between the margins of said panels, and insulating platesfilling the cavity between said panels. When used as components of anexternal wall, the individual wall units are suspended on wall supportsby means of angle brackets. Similar wall units serve as partition wallsextending from floor to ceiling for internal rooms. The thermal andacoustic insulation of such wall units is however, poor.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide a wall unit withimproved thermal and acoustic insulation, whereby corrosion thereof isprevented.

Other objects of the present invention and advantageous features thereofwill become apparent as the description proceeds.

In a wall unit according to the present invention comprising oppositesheet metal panels, seals arranged between the margins of said panelsand insulation accommodated in the cavity between said panels, there isprovided at least one insulating group extending parallel to said panelswhich is composed of two high gloss foils capable of reflecting thermalradiation, and of chambers arranged between said foils, the walls ofsaid chambers consisting of insulating material. Thus a highly effectiveinsulation is attained. Heat absorbed e.g. by the outer panel isimparted to the foil on the inside thereof. From this high-gloss foilfew thermal rays only are radiated, which penetrate through saidchambers, impinge the opposite foil, and are almost completely reflectedby the latter, so that this second foil is heated to a very low extentonly. The walls of said chambers are made of insulating material, e.g.in the form of honeycombs, the webs of which are thin, so that heatconduction through these webs is low. The chambers are small and tightlysealed, so that likewise hardly any heat transfer takes place byconvection through the air.

By arranging several such insulating groups consisting of foils andchambers one behind the other the effect is considerably increased,whereby even the strictest requirements can be fulfilled. Between anysuch groups an insulating plate may be inserted, which reduces thethermal conduction from one foil to the other.

Between the foils also insulating plates e.g. of hardened synthetic foammay be arranged which have on both faces ribs for the formation ofchambers. In order to reduce the contact areas, through which heattransfer takes place, an insulating plate having horizontal ribs isfollowed by an insulating plate having vertical ribs.

Instead of complete plates, strips only may be placed alternately inhorizontal and vertical positions against a reflecting foil interposedbetween them. The recesses between the ribs may be coated withreflecting adhesive tapes or the ribbed plates may be completely coatedwith a reflecting layer or adhesive foil.

The insulating chambers may be formed by narrow insulating plates e.g.of 5 mm. width e.g. of solidified synthetic foam perforated from face toface and tightly sealed on both faces by highly reflective foils, theremaining structure of hardened synthetic foam constituting thegeometrical shape of the chamber walls.

Moreover the cavity between the panels may be evacuated. Any heattransfer by convection is then excluded. This entails the furtheradvantage that formation of condensate and consequent corrosion areprevented.

Further improvement of the insulation is attained by evacuating the airfrom the cavity between the sheet metal panels. For this purpose theindividual wall elements may be provided with valves, or all the wallelements may be connected to a vacuum pump by a pipe line. Evacuationprevents any heat transfer by convection. Moreover, the formation ofcondensate is prevented which condensate might reduce the reflectivityof the high-gloss reflector foils.

The thermal insulation properties of the wall units describedhereinabove apply substantially likewise to acoustic insulation.

When the air is not evacuated, it is preferably displaced by dry air.For this purpose the air-tight wall units are connected by pipe lines toan air drying plant. Corresponding to the atmospheric fluctuations ofair pressure, dry air is additionally received by the wall units fromsuch an air drying plant when the atmospheric pressure rises, and isdischarged by the wall unit into said plant when the atmosphericpressure drops. The pressure in the wall unit thus is at any time insubstantial equilibrium with the atmospheric pressure, without humiditybeing able to enter into the wall unit.

It is, of course, also possible to provide the cavity itself with airdrying material so that the air in the cavity is kept dry. Afterevacuating the cavity and placing the air drying material therein, thewall unit may be air-tightly sealed. Thus on changes in temperature andpressure the evacuated cavity or the cavity filled with air or a gas isalways kept dry so that no moisture can precipitate on the reflectingfoils of the insulating wall unit of this invention.

Thus the present invention consists in principle in providing means inthe cavity of the insulating wall unit which prevents that the degree ofsaturation with moisture of the air or gas in the wall element isexceeded and that water of condensation is deposited on the walls of thecavity of the insulating wall unit and on the reflecting foils. Suchdeposition of water of condensation, especially on the reflecting foils,which otherwise will take place due to the changes in temperature andair pressure of the surrounding atmosphere, will result in a veryconsiderable reduction in the reflection of the heat radiation by saidreflecting foils. The means provided according to the present inventionfor preventing deposition of water of condensation within the cavity ofthe wall unit and on the reflecting foils or the like are adapted topermanently maintain the moisture content of the air or gas in thecavity below a predetermined maximum value, i.e. sufficiently above thedew point of the relative degree of moisture, so that the reflectingsurfaces do not become covered with moisture. Such means are, forinstance,

a. complete or partial evacuation of the cavity of the wall unit whichcan then be air-tightly sealed or which can be connected with a pump;

b. providing a substantially dry air or gas atmosphere within the wallunit, for instance, by placing therein an air- or gas-drying materialand air-tightly sealing the cavity;

c. circulating a substantially dry gas or dry air through the wall unitwhereby the gas or air is passed through a drying system to remove anymoisture present, or accumulating, in said circulating gas or air; or

d. venting the dry air introduced into the wall unit to the atmospherethereby passing it through a dryer so that the dry air, if its volumeincreases due to an increase in temperature, passes out to theatmosphere and if the volume of the air decreases due to a drop intemperature, air is drawn in from the atmosphere through the air dryingdevice.

All these and other means prevent formation of condensate and reductionof the reflectivity of the reflecting foils due to the deposition ofwater of condensation thereon. In addition thereto corrosion of thereflecting foils is prevented or at least very considerably retarded.When evacuating the cavity, any heat transfer by convection is excluded.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the invention are illustrated by way of examplein the accompanying drawings without, however, limiting the inventionthereto. In said drawings

FIG. 1 is a vertical section of parts of two mutually abutting wallunits constituting an external wall fixed to the ceiling of a building.

FIG. 2 is a vertical section of a wall unit with insulation by platesand by honeycombs.

FIG. 3 shows part of an insulating plate having horizontal ribs.

FIG. 4 of a plate having vertical ribs,

FIG. 5 of a plate having interrupted ribs.

FIG. 6 is a section of a wall unit with insulation by strips and plates,and

FIG. 7 is a section of a wall unit with insulation by honeycombs and byplates covered with foils.

FIG. 8 is a vertical section of parts of two mutually abutting wallunits with an external sheet metal panel and an inner gypsum panel andwith insulating reflecting foils and spacing members formed byperforated hard plastic foam plates.

FIG. 9 is a partial elevation of a perforated hard plastic foam platecovered on both sides by reflecting foils.

FIG. 10 is a vertical sectional view of a wall unit having insulatingreflecting foils tensioned by means of springs.

FIG. 11 is a partial elevation of a wall unit having reflecting foilsand spacing members consisting of perforated hard plastic foam strips,the panels and a number of other parts being broken away.

FIG. 12 is a diagrammatic sectional view through a plurality of wallunits of a building, arranged one above the other showing an air dryerand a dust filter and venting to the atmosphere.

FIG. 13 is a diagrammatic sectional view through a plurality of wallunits arranged one above the other, connected to a circulation pump, anair conditioning installation, and a volume compensating device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 sections 1 of Z-shaped profile are attached by means of screws1a to an end face of the ceiling 2 of a building. The upper section 1carries on an outwardly directed flange an upper wall unit 3 and thelower section 1 carries the upper edge of a lower wall unit 3. Each wallunit comprises an outer sheet metal panel 3a and an inner sheet metalpanel 3b. Between the margins 3c, 3d of said panels an insulating andsealing strip 10, preferably of ebonite, is inserted. Screws 11penetrate the margins, the sealing strips 10 and the sections 1. Theypress the sheet metal panels in an airtight manner against each other,and at the same time support the wall units on the building. In thecavity between the sheet metal panels an insulation is accommodatedwhich comprises at least one highly effective insulating group extendingparallel to said panels. This insulating group comprises a thinhigh-gloss foil e.g. of aluminum capable of reflecting thermalradiation, small cells 8 of about 8 mm. width, the walls of whichconsist of insulating material, and a second reflecting foil, thesefoils sealing off said chambers.

In a first embodiment these chambers are formed by honeycomb plates 8a,the webs 8b of which extend between the two opposite foils. Between thefoils of the three insulating groups illustrated there are moreoverinserted insulating plates 9 e.g. of feltboard or solidified synetheticfoam, for reduction of thermal conduction and for stiffening.

For improved appearance and for protection from corrosion each of thesteel metal panels is provided outside with a coating 4 of lacquer orsynthetic material, and inside with a foil 5 of a sound-deadeningmaterial and a stiffening sheet metal panel 6.

Upon solar radiation of the outer sheet metal panel also the adjoiningfirst foil is warmed. However, the high-gloss foil radiates but littleheat inwards, namely about one fifth of the radiation emitted by a blackbody. The heat radiation emanating from the foil penetrates thechambers, impinges the opposite foil and is almost completely (say 93%)reflected by the high-gloss surface of the latter and is absorbed onlyto a small proportion (7%), so that the opposite foil is warmed up butlittle and can discharge little heat (1.25%) only. Heat transfer byradiation is accordingly very small. Moreover heat conduction takesplace through the edges of the webs of the honeycomb contacting thefoils. However, since the cross-sectional area of the webs contactingthe foils amounts to about 4% only of the whole area of a foil, and thewebs consist of insulating material, also the heat conduction is verylow. Finally heat could be transferred by convection through theenclosed air. However, since a great many and consequently small cellsare formed by the honeycomb plates, an air flow and consequent heattransfer can hardly take place. When several insulating groups arearranged in series, their effect is greatly increased. In a test withfive insulating groups, the outer sheet metal panel was raised to atemperature of 100° C. and kept at that temperature, while the innersheet metal panel was exposed to a room temperature of 20° C. After 4hours a steady condition was attained in which the temperature of theinner sheet metal panel had increased from 20° C. to 30° C. At anexternal temperature of 70° C. the temperature of the inner sheet metalpanel rose by 7° C. and at an external temperature of 45° C by 3° C.only.

The walls of the honeycomb cells may be provided with highly reflectivevery thin metal surface layers (e.g. by deposition of aluminum from thevapor phase in vacuo). For reasons of fire protection the honeycombs maybe made fire-proof by impregnation or the like. Likewise mats of glassfibers may be arranged as an insulation on the internal surfaces of thewall panels as well as e.g. between two aluminum foils whereby the wallunits, in conjunction with the reflecting metal foils and sheet metalpanels (thermal reflection) and the impregnated and hardened honeycombs,are made extraordinarily fireproof.

The gaps between any two adjacent wall units may be outwardly closed byangle sections 13 held by screws 11 and by screens 14, which engagebehind resilient tongues in said angle sections. For further thermal andacoustic insulation from the interior space the inner sheet metal panelsmay each carry a reflecting foil 7 and spacer strips 15. On the latter aplate 16 of plaster of Paris and covered on both surfaces withreflecting foils 7 is placed, which is attached to the buildings byangle sections 17 and forms the inner wall surface thereof.

The cavity between the sheet metal panels 6 with foils 7 may beevacuated through perforated pipe 75 which is connected to a vacuum pump(not shown), and then sealed. Or the air in said cavity may be replacedby dry air or a dry gas such as nitrogen through said pipe 75 and thenalso sealed. Or perforated containers with a drying agent such ascalcium chloride, silica gel, or the like (not shown) may be placed intothe cavity which is then sealed, so as to dry the air therein. Or dryair or a dry gas may be circulated through the cavities of superposedwall units in the manner shown in FIG. 13. Or the cavity filled with dryair may be vented to the atmosphere as shown in FIG. 12. Any means toprovide dry air or a dry gas atmosphere in the cavity of the wall unitsaccording to the present invention may be employed provided theymaintain a dry air or gas atmosphere under subatmospheric, atmospheric,or superatmospheric pressure in the cavity and thus prevent depositionof moisture on the walls of the wall unit and especially on thereflecting foils thereon.

A second embodiment of the present invention is illustrated in FIGS. 2to 5. The wall unit 3 comprise an outer sheet metal panel 3a and aninner sheet metal panel 3b. Each of them has a coating 4. The insertedinsulation comprises six insulating groups. The two middle groups aremade of honeycomb plates 8a as in the first embodiment. The outer groupsare formed by insulating plates 51, e.g. of hardened synthetic foam,which have narrow ribs 51a about 5 mm. wide on both faces and formstrip-shaped cells 8. In FIG. 3 an insulating plate is illustrated inelevation having horizontal ribs 51a, in FIG. 4 a plate with verticalribs 51b and in FIG. 5 one with rows of projections 51c.

The first insulating plate is followed by a second reflecting foil 7 andby a second insulating plate, the ribs of which run at right angles tothose of the first insulating plate; Thus thermal conduction can occurat the crossing points only of the ribs. A third reflecting foil 7 sealsthese cells off. Between the insulating groups sheet metal panels 9 maybe arranged which prevent any buckling of the thin reflecting foil undermajor pressures e.g. upon evacuation, which may be caused by the webs ofthe honeycomb plates or ribs of the insulating plates beingjuxtapositioned to each other on points only.

When the sheet metal panels 9 themselves are highly reflective, thefoils may be dispensed with.

These wall units may also be provided with dry air or a dry gasatmosphere or may be evacuated as described hereinabove.

In a third embodiment of the present invention, instead of insulatingplates, insulating strips only are used, the contact surfaces of whichhave ribs. In FIG. 6 the sheet metal panels 3a, 3b are providedexternally with coatings 4. The first insulating group is formed byhorizontal insulating strips 52 with ribs 52a, which may be attached byglueing to the contacting reflector foils 7. The second group hasvertical insulating strips 53 with ribs 53a. Then follows a third groupwith horizontal strips and a fourth group with vertical strips. In thecells between these insulating strips heat transfer by convection hardlyoccurs. In the middle of the unit two groups are arranged each withinsulating plates 51 having horizontal ribs and corresponding reflectorfoils. Moreover reflector foil strips 7a are inserted into the recesses,whereby thermal radiation into the insulating plate is strongly reduced.

In a fourth embodiment of the present invention according to FIG. 7 twoinsulating groups comprising honeycomb plates 8a and associatedreflector foils 7 contact each of the sheet metal panels 3a, 3b frominside, which panels have coating 4 outside. In the middle an insulatinggroup is arranged comprising an insulator plate 51 having ribs 51a onboth faces. These ribs may be produced by pressing or rolling. At thesame time reflector foils may be attached by glueing, so that thesurfaces of the insulating plate are completely covered by reflectorfoils.

Instead of being made of sheet metal, the external panels of the wallunit may be made of the other materials, e.g. of synthetic substances.As in the preceding wall units, these wall units may also be providedwith dry air or a dry gas atmosphere or may be evacuated as describedhereinabove.

In FIG. 8, an example of a suitable wall unit is illustrated inlongitudinal section. Seven insulating groups with insulating foamplates 71 lie against the outer sheet metal panel 3a, which has an outerlayer 4. As shown in FIG. 9, the insulating foam plates have cylindricalperforations 71a. The perforations are tightly closed on both sides byreflecting foils 7, which form narrow insulating chambers or cellscontaining stationary dry air or gas. In order to reduce the contact andaccordingly reduce the heat conduction, it is advantageous for thesurfaces of the insulating plates to be roughened. Towards the innerside of the cavity, the wall unit is closed by a plaster plate 16 whichis clad, towards the last insulating group, with a reflecting foil 7.The marginal sealing of the wall unit is effected by insulating strips51, for instance of solid foam. The outer wall panel 3a and the plasterplate 16 are connected through the insulating strips, by means ofplastics screws 72. For this purpose, on the inner side of the wallpanel 3a, a nut 72a is welded by the stud welding method. For connectingan upper and a lower wall unit, the sheet metal panel margins areprovided with angled portions, the lower panel having the U-shaped angleformation 3e and the upper panel having the L-shaped angle formation 3d.The mutually engaging angle formations are connected by rivets 73. Afterfixing, an insulating margin filling strip 52 is pushed into the opengap between the upper and lower wall units. In this example, the sheetmetal panels are mutually supported and can withstand pressure.

The insulation can be increased by evacuation of the cavity between thesheet metal panels. For this purpose, the individual wall units may beprovided with valves and/or all wall units may be connected through apipe with a common evacuating installation (not shown). The evacuationexcludes heat transmission by convection. Moreover, formation ofcondensed water is prevented, which would reduce the reflectingcapability of the highly polished reflecting foils.

For avoiding pressure differences, hoses or pipes 75 may extend throughthe plaster plate 16 into the interior of the wall unit, which connectthe cavity of the air-tight wall unit with the atmosphere, through anair drying installation, or connect it with a volume compensating deviceas shown in FIGS. 12 and 13.

Pipe 75 may also be used for evacuating the cavity between the sheetmetal panels. For this purpose said pipe 75 is connected with a vacuumpump (not shown) and a valve (also not shown) is interposed betweenvacuum pump and wall unit. After evacuating the cavity of the wall unit,the valve is closed and the pipe leading to the pump as well as the pumpare removed. They can be attached again for subsequent evacuation if theneed arises.

The example of FIG. 10 enables a still smaller use of insulatingmaterial. The outer panel 3a and the inner panel 3b are covered on theoutside with a coating 4 and are internally clad with a reflecting foil7. In the cavity further reflecting foils, for instance, highly polishedaluminum foils are mounted under tension, for instance, at spacings ofonly a few millimeters, preferably 5 to 10 millimeters. For thispurpose, the upper margins of the foils are fixed onto fixing strips 76,preferably of hard foam, for instance, by an adhesive coating 76a, andthe fixing strips together with the foils are inserted into the panelsand substantially air-tightly connected between themselves and with thepanels. The lower margins of the foils are rolled around metal strips 76and are simultaneously bonded. The metal strips have poles for theprovision of links 78a which can be suspended on springs 78. In a mirrorsymmetrical arrangement, the other ends of the springs are securedthrough metal strips onto foils, the other ends of which are held byfixing strips between the panels. The foils may be provided with spacingstrips 77 above the metal strips, which are held on only one side by anadhesive coating 76a, the other side simply lying in free contact andallowing the passage of air. The panels are provided at the upper marginwith L-shaped angled portions 3a and at the lower margin with U-shapedangled portions 3e, so that abutting wall units can be pushed one intothe other in a tongue and groove-like manner. The cavity between theangled portions 3e is closed off by marginal strips 54 of hard plasticsfoam. For reinforcing, the marginal strips may be surrounded by arectangular tube 55 of plastics material and the tube can be air-tightlyincorporated, with the aid of rubber strips 56. For complete airclosure, the rectangular tube 55 and the strips 54 may be horizontallysubdivided and stuck together again with the interposition of a metalfoil 57 as a vapor barrier. Into the intermediate space between thelower fixing strips 76 and the spacing strips 77, a pipe 75, forinstance, of plastics material extends, the pipe being connected througha pipe network to the atmosphere through an air drying installation, orbeing connected to a compensating device or with a vacuum pump toevacuate the cavity.

Instead of the cavities in the wall units, and the circulatory systembeing filled with air, other dry gases, for instance, nitrogen may beused. This has the advantage that the surfaces of the aluminum foils arenot oxidized.

In accordance with the front elevation shown in FIG. 11, reflectingfoils 7 may be held on all margins by fixing strips 76. The cavitybetween the foils is subdivided into chambers or cells by perforatedinsulating strips 81. By showing in FIG. 11 individual foils cut away,the chambers or cells between the foils 7a and 7b, formed by horizontalinsulating strips 81a, and the cavity between the foils 7b and 7c,formed by the vertical insulating strips 81b and so on, can be seen.

In place of using insulating strips 81a and 81b between the foils 7a,7b, and 7c of FIG. 11, there may be glued small disks, blocks, or thelike of insulating material upon the reflecting foils, thus creating thesmall chambers or cells of the wall units. Of course, as statedhereinabove, perforated plates, for instance, of hardened plastics foamcan be arranged between the reflecting foils or other suitableinsulating means can be provided therebetween. The reflecting chambersor cells can also be formed by providing recesses, crevices, or the likeopenings in said plates. It is also possible to use insulating strings,cords or the like in place of the insulating strips shown in FIG. 11 inorder to form the reflecting chambers or cells.

FIG. 12 shows in which manner a plurality of wall units arranged oneabove the other can be filled with air. The plurality of wall units areillustrated by their outer panels 3a and their inner panels 3b. In frontof each wall unit, a horizontal pipe 75 is shown which is in thevicinity of the upper end of each wall unit and which leads to acollecting line 141 which in turn leads to an air drying device T and adust filter S which has an opening 144 to the atmosphere. If thetemperature of the dry air in the wall units drops, and the airconsequently decreases in volume, then air is drawn in from theatmosphere through the dust filter and the air drying device. If thevolume of the dry air increases, then dry air passes out through theopening 144 to the atmosphere.

Even more reliable results are obtained by preventing deposition ofmoisture which occurs in cooling down the wall unit, by causing dry airor gas to circulate throughout the wall units. In FIG. 13, theindividual wall units are illustrated by their outer panels 3a and theirpanels 3b. The cavities of the wall units are connected at their lowerregions by transverse pipes 137a with openings 137b, to a common supplyline 137, and at the upper regions by transverse pipes 133a withopenings 133b, to a common take-off line 133. The take-off line leads toa circulating pump P, a dust filter S, a dryer T, a volume compensatingdevice V and back to the common supply line 137, so that the path ofcirculation is closed.

Preferably, this circulation can also be used for performing atemperature conditioning of the wall units, that is to say heating orcooling them according to requirements. For this purpose, a coolingdevice K and a heating device H with thermostat control are additionallyprovided in the circulation path of the dry air. Furthermore, the dustfilter has an opening 144 leading to the atmosphere, in order to be ableto make up for losses of dry air. Said opening 144 may also lead to agasometer (not shown) partly filled with a suitable gas such asnitrogen, also in order to make up for losses of dry gas if the wallunits are filled therewith. Conditioning of the wall units in thismanner will prevent deposition of moisture and will facilitateconditioning of the interior of a building constructed of the wall unitsof the present invention.

It is, of course, understood that evacuating the wall units of thisinvention or providing them with an atmosphere of dry air or a dry gasmay be effected by other means and methods as those described herein.

For simplifying the guiding of the dry air or gas, the collecting linesmay be disposed in the wall units. The cavities of the wall units maythemselves be constructed as air or gas channels. Advantageously,directly in front of the separating wall, an air or gas channelextending from the bottom to the top may be provided as a supply line,and in the uppermost wall unit a bypass channel may be provided, as wellas a channel extending from the top to the bottom behind the outer wall,serving as a take-off line. For forming the air or gas channels, theouter walls may comprise vertically directed ribs, the spacing membersmay be vertically arranged and corrugated reflecting foils may be usedwith their vertical corrugations superimposed.

The outer panels may be air-tightly built together to form a wallsuspended from the building; and an inner wall unit with insulation maybe arranged at a spacing therefrom forming an outer air channel, and theinner wall may again be arranged at a spacing, forming an inner airchannel.

For air conditioning the rooms from the outer walls, water containers,i.e. in the form of square tubular pipes may be arranged on the innerwall of the wall unit, for the supply or removal of large amounts ofheat through the inner wall. The water containers simultaneously servefor strenghtening and holding the inner wall so that the reflecting foilinsulation may be mounted directly between the floor and the ceiling andthe intermediate chambers formed by bores in the cover and base may beconstructed as air or gas channels. For partition walls in the interiorof the building, an inner wall unit may be provided between two walls,with the formation in each case of an air channel, which is filled withdry air and provided with a volume compensating device. The air channelsmay be connected by an air circulation system to an air conditioninginstallation, preferably using dry air, and may serve for airconditioning the walls and the rooms lying therebeyond.

The insulation may consist of reflecting foils arranged at a spacing,the spacing being maintained by perforated foam plastics plates. Thereflecting foils may alternately be fixed only at their margins to hardplastics foam rails, and held by means of tension springs. The cavitybetween the reflecting foils may be subdivided into chambers or cells bya number of narrow perforated strips of hard foam plastics, the stripson one side of the reflecting foil being horizontal and those on theother side vertical. The reflecting foils may be strengthened by theprovision of corrugations and inserted into the chambers with theinterposition of spacing members. Foils with large corrugations may beheld between tensioned bands or cords which are arranged in a zigzagmanner.

The volume in the wall elements which has to be kept filled with dry airor another dry gas, for instance, nitrogen, can be essentially reducedby the insertion of insulating elements which themselves are air-tightlyclosed. This can consist of an air and vapor-tight flexible envelope ofplastics which is stiffened by two plates lying parallel to the panels,filling the cavity of the wall unit parallel to the walls and beingfilled with dry air. The volume compensation can be obtained by changingthe spacing of the plates and by a bellows-like construction of theenvelope. Insulation, for instance, frames with reflecting foils mountedon them, may be provided in the interior.

For enabling the use of very thin reflecting foils of aluminum, whichare particularly suitable, marginal strengthening members, for instancestrips, may be provided for them. While the foil is being unrolled, itslongitudinal marginal edges are bonded to self-adhesive strips andduring cutting of the foil to size, its transverse marginal edges arebonded to such strips, the strips being drawn from rolls. The adhesivestrips may be folded over the margins of the foil and may be providedwith perforations for facilitating mounting of the foil.

The disclosure of copending application Ser. No. 37,068 which describesother ways and means of providing the wall units with dry air or anotherdry gas is included by reference in the present application.

The wall panels of the wall units according to the present invention maynot only be made of sheet metal but may also be composed of woodenplates, gypsum plates, plates of asbestos cement as known, for instance,under the trademark "ETERNIT," hard rubber plates, and others. Theinsulating systems within the cavity of the wall units may consist ofpressure resistant honeycomb structures made of kraft paper,resin-impregnated paper, hardened plastic foam plates, and the likeinsulating materials. Non-metallic wall panels are preferably coatedwith plastic coatings which can be electroplated, and are thenelectroplated. Thereby, the wall panels are made substantiallycompletely impermeable to vapors.

The wall units according to the present invention can be used not onlyas structural parts, separating walls, ceilings, and floorings in theinterior of buildings but also as external structural parts, since theirdurability and service life is considerably increased and prolonged.

As stated hereinabove, surface condensation and deposition of condensedwater due to changes in temperature and pressure can be prevented notonly by introducing dry air or gas into the cavity of the wall unitsaccording to the present invention, but also be partial or completeevacuation of the air from said cavities, chambers, or cells.

In order to dry the air in the wall units, especially when the air isnot completely evacuated, there can be inserted, as explainedhereinabove, perforated containers, capsules, or the like which arefilled with a hygroscopic agent capable of absorbing the moisturepresent in the air, preferably in the lower part of the cavity of theair-tightly sealed wall unit. Preferably a subatmospheric pressure inthe wall unit which is slightly below the lowest barometric pressure tobe expected in utilizing the wall units, is maintained therein. Sincethe marginal parts of the wall units cannot be composed of metal but, inorder to avoid formation of heat transfer bridges, are preferably madeof highly insulating materials such as expanded plastic or hardenedplastic foam, a vapor barrier layer or vapor blocking layer must beprovided if the air in the wall unit is under subatmospheric pressure orif it is substantially completely evacuated therefrom. For this purposethe marginal strips, borders, bars, or the like of hardened plastic foamare coated with a thin plastic layer which is capable of beingelectroplated and which is subsequently provided with a metallicskin-like layer by electroplating. Said layer must, of course, be thinenough so that substantially not heat transfer bridge is formed.

It is, of course, also possible to use marginal strips 54, for instance,of FIG. 10 which are subdivided into two parts and have interposedtherebetween, for instance, an aluminum foil 57 as a vapor barrier.Likewise, the rectangular plastic tube 55 surrounding said marginalstrips 54 may be electroplated on its inner and outer surfaces. Likewisethe plastic foam strips, plates, and the like insulating inserts can beelectroplated to provide a thin metal coating after coating them with aplastic layer capable of being electroplated.

An especially useful wall unit according to the present invention isobtained by modifying the wall unit as illustrated in FIG. 1 as will bedescribed hereinafter.

As is evident from FIG. 1, the wall unit actually consists of twoinsulating wall units, the one wall unit which may be called hereinafterthe primary wall unit being formed by the panels 3a and 3b and the otherwall unit which may be called hereinafter the associated wall unit beingformed by the inner panel 3b and the gypsum or Plaster of Paris plate16. Panel 3b and plate 16 with spacer strips 15 form the space orchamber 15a. This hollow space 15a thus forms an all around closedassociated smaller wall unit.

Like the chambers or cells 8 of the primary wall unit, space 15a canalso partly or completely be evacuated by means of valves and a pipeconnection to a vacuum pump. Or a dry air or dry gas atmosphere can beprovided therein, for instance, by inserting drying agents in said spaceor by allowing the air in the space to communicate with the atmospherewith the interposition of an air drying plant or by causing dry air or adry gas to circulate through said space 15a by means of a circulatingpump, a dryer, and a volume compensating device as shown in FIG. 13.

The primary wall element serves the purpose to achieve an extremely highthermal and acoustic insulation effect. This is primarily achieved bykeeping its cavity free of moisture or by keeping its moisture contentat least below the dew point so that formation of condensed water isprevented. In addition thereto, the associated secondary wall elementwith space 15a has the important function that any condensed water whichprecipitates on the surface of the gypsum or the like plate 16 due tochanges in the temperature of the interior of the respective building,is absorbed by the plate 16 and is transferred to space 15a from whereit is eliminated by means of the air drying plant.

In order to achieve this result, foils 7a which are provided at theouter surface of interior plate 16 and foils 7b which are provided atthe inner surface of plate 16 and on panel 3b with its lacquer coating 4can either be perforated high-gloss aluminum foils so that condensedwater can be transferred through plate 16 into space 15a. It is, ofcourse, also possible to completely omit said foils 7a and 7b so thatthe condensed water can readily enter space 15a through plate 16. Thusthe primary and most important function of the associated secondary wallunit 3b, 16 forming space 15a is the dehumidification of the interiorplate 16. If space 15a were not provided, satisfactory dehumidificationof plate 16 would not be possible.

It is, of course, also possible to attach the plate 16 directly to thepanel 3b provided said panel 3b is also permeable to moisture and thuspermits transfer of the water condensed on plate 16 through said panel3b into the cavity of the primary wall unit where it is eliminated byevacuation, by the drying agent inserted into said cavity, or by the airor gas drying plants interposed in the circulating air or gas or the airor gas flow communicating with the atmosphere or a gasometer.

Of course, many changes and variations in the wall units according tothe present invention may be made by those skilled in the art in orderto effect reduction of the vapor pressure of the gas present in the wallunit to such an extent that condensation of water vapor does not takeplace.

Thus, for instance, the insulating means, strips, spacers, ribs, plates,or the like may be polystyrene foam plates, insulating mats, glasswool,rock wool, felted plates, asbestos plates, or the like. Acousticinsulation can be achieved, for instance, by providing, preferably atthe inner surfaces of the wall panels, as sound deadening or absorbingmeans highly viscous or highly polymerized plastic sound damping orabsorbing materials such as vinyl acetate copolymerization productsand/or sound damping or absorbing plastic foils, such as made ofvinylchloride copolymerization products. Such sound damping or absorbingmeans are advantageously sandwiched between the wall panels and opposedsheet metal or the like panels preferably of the same thickness.Acoustic insulation and sound absorption are very considerably improvedby such means.

I claim:
 1. In a wall unit comprising panels laying at opposite faces ofsaid unit, a seal arranged between the margins of said panels toair-tightly seal the wall unit, and an insulation occupying the cavitybetween said panels, the improvement which consists in additionallyproviding the wall unit at its one side with an additional panel, spacedfrom the wall unit and forming therewith an associated cavity, saidadditional panel being permeable to condensed moisture, air, and vaporsand allowing the condensed moisture deposited thereon to passtherethrough into said associated cavity, said associated cavity servingto eliminate moisture condensed on said additional panel.
 2. The wallunit of claim 1, in which the additional panel is a gypsum panel.
 3. Thewall unit of claim 1, in which spacing means are provided in theassociated cavity.
 4. The wall unit of claim 1, in which the associatedcavity is air-tightly sealed toward the wall unit.
 5. The wall unit ofclaim 4, in which means are provided to reduce the vapor pressure in theassociated cavity sufficiently to prevent condensation of water vaportherein.
 6. The wall unit of claim 4, in which said means is means toevacuate the associated cavity.
 7. The wall unit of claim 4, in whichsaid means comprises a dry gas atmosphere in said associated cavity. 8.The wall unit of claim 4, in which said means comprises dry air in saidassociated cavity.
 9. The wall unit of claim 1, in which the walls ofthe associated cavity are provided with foils capable of reflectingthermal radiation, the reflecting foil adjacent the additional panelbeing permeable to condensed moisture.
 10. The wall unit of claim 9, inwhich at least the surface of the additional panel opposite the onepanel of the wall unit is provided with a perforated reflecting foil.11. In a wall unit comprising panels lying at opposite faces of saidunit, a seal arranged between the margins of said panels to air-tightlyseal the wall unit, and an insulation occupying the cavity between saidpanels, said panels, seal, and insulation forming the primary wallelement, the improvement which consists in additionally providing thewall unit at its one side with an additional panel, said panel beingdirectly attached to the one panel of the wall unit, said additionalpanel being permeable to moisture and thus permitting transfer of thewater condensed on said additional panel to pass through said additionalpanel and said panel of the wall unit into the adjacent cavity of theprimary wall unit, said cavity being provided with means to eliminatethe moisture condensed on the additional panel and introduced thereintothrough the additional panel and the one panel of the wall unit, saidadditional panel being permeable to condensed moisture, air, and vapors.